LED Matrix 8x8 is not lighting at all after following official tutorial.

Yeah, well I recently got an Arduino Uno. This is like my 15th project (I am a beginner with 20 days experience). So, what I want is a specific LED of the Matrix should light up. The light can be toggled from one led to another by 2 potentiometers. But, NOTHING HAPPENS!
I mean, there is 100% NO CHANGE in the board or hardware.
I followed the https://www.arduino.cc/en/Tutorial/RowColumnScanning Tutorial.
Help required.
Yash

Trial_LEDMatrix.ino (1.38 KB)

Are you sure you have the row anode-column cathode LED matrix?
The other type is the row cathode-column anode.

The sketch you have supplied does not have a setup() or loop() function, it has a main(). I am guessing that this did not come from the arduino.cc website. I does not match what is at the link you provided.

Please post a corrected link and sketch, a photo or drawing of your matrix with the connections to the Arduino.

@marco_c : Oh sorry. Here it is. I accidentally posted the very first sample of code that did not make sense to me, so I took the official code. Attachment below.

@ieee488 Well, I don't know. Is there a method to differentiate? It looks a little similar to what the website has got. (excluding minor differences).

I will send the picture on my mobile device in a few minutes.

Trial_LED-Matrix.ino (2.83 KB)

Just a few edits to the official thing :

  1. I did not know how to connect two pins to same 5V pin , so I connected 1 potentiometer to Pin 5V and the other to 3.3V pin. Googled and found that both pins are always active, so...
  2. The wiring did not show any resistors, so I did not even use one. Is that stupid?
  3. And the major part was that I connected two LARGE breadboards together after taking out the thin-outside thingy instead of, as in YouTUBE, only one breadboard/ the green thing called MAX7219.

Sending picture right away.

Here it is.A me please go through what I edited and please tell me if I did anything wrong.

P.S. I don't know what or how to do arrays. And I guess the thing above was a .. wiring diagram? G
I didn't use the schematic on that tutorial to be honest.

YashGuy65:
I didn't use the schematic on that tutorial to be honest.

WTF!?!?!

ieee488:
WTF!?!?!

Hmm.... Do I HAVE to go through it?... I just went through the wiring thingy. Looked like it would legibly work

Honestly, what we are reading sounds a lot like "I made a cake, did not follow the recipe and used different ingredients. It doesn't taste nice - where did I go wrong?"

From the picture, the way you have connected breadboards will not work. There is no electrical connection across the middle gap in a breadboard. It is designed so that an IC can be placed over the gap and the legs are on either side. This needs to be fixed before continuing.

@marco_c : OK. Lemme try the CONNECT BREADBOARD stuff you said.
Will post results in some time.

P.S. Well, I think I will learn to read schematics and implement them by today. I mean, it wouldn't take much time for a 7th grader, right?

@ieee488 OK. Fine. Schematic shall be implemented soon. Guess, that's the mistake I did

AND , BTW I googled to make sure all that I did was valid (except for breadboard connections).
I mean, I can't connect TWO pins at the same time to the same 5V connection, right? I mean, that isn't possible without harming my lil' UNO, right?Just tell me if that is possible, and I 'll do it. Cuz in my potentiometer datasheet, 5V was OK.

marco_c:
Honestly, what we are reading sounds a lot like "I made a cake, did not follow the recipe and used different ingredients. It doesn't taste nice - where did I go wrong?"

From the picture, the way you have connected breadboards will not work. There is no electrical connection across the middle gap in a breadboard.

OK, SO should I connect the breadboard side thin leg looking pieces? And I used the same ingredient except for the 3.3V for the second potentiometer. Should I add extra wiring after adding what you said about potentiometers?

I can't connect TWO pins at the same time to the same 5V connection, right?

Yes you can providing that you are not exceeding the current that the Uno power supply can provide. This is one reason that you will need to put current limiting resistors on the outputs from the Uno connected to the LEDs.

In fact, if the whole circuit is to be powered by 5V, then you probably should not be using the 3.3 V at all.

should I connect the breadboard side thin leg looking pieces?

The thin side pieces are power supply rails (usually with 2 rows of holes). These are so that you can connect 5V and ground to those (from the Arduino) and all the other power stuff can connect to that. The breadboard connections along here are on the along the length of the board, usually with a split in the middle. It is worth your education to test how these are connected using a multimeter in continuity test mode.

If you connect the power bus pieces, it should space out the bigger boards more and you can connect the matrix and wires to its pins on connected slots of the breadboard.

So, I got your point.
Can you just verify the next post?
I am setting it up while learning to read schematics and Ohm's law from How to Read a Schematic - SparkFun Learn
Hoping it is fully correct.

Should there be ONE 'power rail' between the 2 breadboards?
Well, then I just need to connect THAT to the potentiometers too, right?

Sorry for you having to sorta, umm, 'spoon-feed' me ....as the teachers say. Just that I am a beginner.

The critical thing for your situation is to get the LED matrix so that you can connect the wires. 1 or 2 power rails is not that relevant as they are simply used to space the BB apart. I would guess 1 is enough from what I can see, but you are a better judge. You actually only need 1 for connecting wires. You should then connect all 5V and grounds to the two rails.

Suggest that you also read 'How to use a breadboard' from the same site.

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Thank you very much. It works well.